Inertia is the tendency of a body to oppose changes to its state of motion. DO NOT USE THIS TAG for moment-of-inertia!

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How does a mobile phone vibrate without any external force?

How does a mobile phone vibrate without any external force? By Newton's law, any body can't move without any external force
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4answers
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Rotating the bucket in circular motion without spilling water

In the bucket experiment when the bucket reaches the top of the circle why will it have a normal force acting on the water downwards? Doesn't normal force oppose any other force? There is no force ...
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1answer
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Why bikes are made lightweight?

From Wikipedia: The most important characteristics about a racing bicycle are its weight and stiffness. If I understand correctly, the greater the weight of the body, the greater its inertia ...
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4answers
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Does a box containing photons have more inertia than an empty box?

A box containing photons gravitates more strongly than an empty box, and thus the equivalence principle dictates that a box containing photons has more inertia than an empty box. The inescapable ...
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1answer
115 views

Angular velocity of disc from induced motion

I came across a question regarding linear momentum $L$ and it's conservation, however I tried and got confused. It reads: A $40kg$ girl stands on the very edge of a rotating disc of mass $50kg$ and ...
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3answers
93 views

Centripetal and Centrifugal force

If water stays in a pail of water that is whirled around a circular path, the water stays in the pail. But is it because of centripetal force or inertia? I'm getting confused by all the different ...
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1answer
34 views

Moment of inertia and gravity

Would the objects have moment of Inertia if there was no gravity? Because imagine a bar, if I put my hand at the center of the bar and rotate it, it would be easier than rotate the bar picking one ...
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4answers
508 views

What truly is mass, and is there a direct way to measure it?

We know a mass of an object of one kilogram as an object that weighs W = mg = 9.8 N and we reference it to that, (when it should as a fundamental parameter describe weight not the opposite). But if we ...
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3answers
272 views

If a vehicle (bus, train) rapidly stops (or accelerates, or turns), why don't our hair or clothes move from the inertial force?

Many times I was sitting in a train, watching closely nearby people. If the vehicle changes it's movement rapidly (brakes, turns, etc), then obviously, people feel the inertial pseudo-force that ...
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1answer
300 views

What is the meaning of “moment”?

What is the meaning of moment? I'm little confused about the word as there are some terms like moment of momentum, moment of mass, moment of force, etc. I want to know what exactly is meant by the ...
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0answers
14 views

Inertial force of fluids [duplicate]

Reynold's number is the ratio of inertial force to viscous force.I also know the definition of inertial force.but where does a fluid get this force from?what are the factors responsible for this ...
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1answer
23 views

What is the minimal G-force curve in 2-dimensional space?

Given two parallel roads, which need to be connected, what shape of curve would produce the minimum overall horizontal G-force(s) on travelers? Is it a $sin$ or $cos$ wave? Is it a basic cubic ...
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3answers
49 views

The principle behind Inertia and it's connection to Equilibrium

Inertia is the tendency of a force-free body to remain in that state or it is something that opposes any act of changing its equilibrium state. Mass is a measure of inertia. I have some questions ...
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2answers
59 views

What is the relationship between potential energy and inertia?

It seems to me that the two are very similar! Potential energy seems to either explain, or partially explain, directly or indirectly, the law of inertia. I already know that bodies do not move because ...
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1answer
26 views

Does stretching a spring with a relatively high spring constant value require more force because of its inertia?

Other than the fact that a spring has a relatively high spring constant (say 1000 N/m) and therefore requires more force per meter to stretch (not bend or twist).
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1answer
43 views

Question about friction in rolling without slipping?

I was under the impression that for a ball/cylinder to roll without slip, there must be a static friction force that opposes the direction of motion. Why, in this case, does the friction act in ...
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1answer
72 views

Can you lift heavy objects in zero gravity? [closed]

I'm not someone who majored in physics and i never took the subject seriously when i was in school and im regretting that alot, there's so many things going in my mind that i cannot answer because i ...
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3answers
81 views

Why charge is not a measure of inertia?

We know that mass is the measure of inertia of rest. Then why charge is not a measure of inertia? What causes the difference between charge and mass?
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3answers
7k views

Does inertia increase with speed?

I have heard that when the speed of the object increase, the mass of the object also increase. (Why does an object with higher speed gain more (relativistic) mass?) So inertia which is related to ...
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1answer
32 views

How to compensate a top-heavy platform [closed]

I have a small four-wheeled platform weighing 1.3kg with a height of 30cm. Its center-of-mass is located at 75% of the height, making it a little top-heavy. I empirically measured the angle at which ...
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3answers
3k views

Could an asteroid land slowly on Earth's surface?

The concept in my mind is that an asteroid is on a vector similar to Earth's, but slightly slower (e.g., 50kmh slower). As Earth passes it, it enters the atmosphere at a sharp angle, and since Earth ...
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1answer
40 views

Newton's second law of motion and viscosity [closed]

In a Coutte flow, the applied force on one of the plates can be expressed by $F = \eta A \frac{dv}{dz}$. F here can also be defined using Newton's second law of motion, $F = m \frac{dv}{dt}$. The ...
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2answers
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Does mass as a measure of inertia have a meaning in zero gravity? [duplicate]

Mass apart from the amount of material, is also a measure of the inertia of an object, ie. the resistance to change its motion. In zero gravity, does still mass count as the amount of inertia? In ...
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1answer
65 views

Does inertia have anything to do with conservation of energy? [closed]

I have googled this and not found anything. It seems to me that if objects at rest did not resist being accelerated (which is what I once thought was the case in outside of gravity like in outer ...
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1answer
42 views

Friction Resulting from Differing Masses

A friend and I are curious about something. We created a ramp from some wood (like a skate ramp) that's not purely circular in nature. We did so with the intent to test how the mass of an object can ...
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2answers
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Does the Inertia of a Cue Ball Affect its Reflection Angle off a Resting Billiard Ball?

Consider the following Diagram in which a Cue Ball (A) of mass M is shot twice at another pool ball with identical mass M. When the force with which the cue ball (A) is hit (v1) is increased (v2) ...
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44 views

Reason behind Inertia

Has any physicist work on the reason behind Inertia? Why do we have inertia only during acceleration? No inertia during constant velocity.
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154 views

Concept of mass

In classical mechanics, there seems to be a need to distinguish between inertial and gravitational mass. Some texts show how the concept of mass may be defined with some mathematical rigor. There is ...
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4answers
107 views

When is the direction of the static friction negative?

i thought that the force of static friction exerted on an object is always going in the opposite direction of any other force exerted on the same object. however, this problem seems to disregard that ...
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1answer
87 views

How does an Atoms electric field overcome an electrons inertia?

An electron has mass, and therefore has inertia. How does an atoms electric field perpetually overcome an electrons inertia, necessary to hold it in its shell? Does this require continual work to be ...
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1answer
40 views

“Mass is a measure of an object’s ability to resist motion or movement of any kind”

This statement is presented as wrong, but I dont understand why. Specifically, what is the diff between motion and "movement of any kind"? Its to do with a question about inertia. I understand that ...
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2answers
77 views

Mass, velocity and inertia [closed]

If 5 ozs of weight is my engine, and this weight starts in the back of a four wheeled vehicle traveling down a decline gaining speed due to the engine mass to allow its inertia to carry it across a ...
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1answer
41 views

Doubts About Force and Inertia!

But then what does inertia mean at all!? Cant we calculate how much it resists the applied force? I mean considering an imaginary plane with no friction but gravity as of Earth and an enormous mass of ...
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3answers
157 views

How to account for inertia in kinematics?

Alright, I'm only in AP Physics and I asked my teacher and he couldn't help me... I'm making a 2D physics engine and I'm having problems when it comes to gravity between objects and I think its ...
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Understanding the inertia matrix of a tilted ellipse

I would like to control the rotation of an ellipse which is tilted by 45° with respect to the rotation axis, and I need to calculate the inertia of the load on the shaft. To be clear, on this figure I ...
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1answer
59 views

What causes the skidding of the wheels of a moving car? Momentum or inertia?

In a moving car, when brakes are applied suddenly the wheels skid.I have these two explanations in my mind and both seems correct to me.1. The momentum of the car must be conserved so the car ...
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3answers
234 views

Inertia on relativistic mass when particle is near speed of light

Inertia is directly proportional to mass but what happens when something travel to speed near to light. Its relativistic mass tends to infinity but that is false mass so I want to know if inertia is ...
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1answer
63 views

How to sensor Jerk=$d^3{\bf r}/dt^3$, or higher derivatives (4th, 5th, 6th order) when applied in the equation of motion of a ballistic missile?

Given a 6th order differential equation of motion as usually used in ballastic missile dynamic models. What kind of sensors are usually used to measure Jerk, (or higher order derivatives in ...
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1answer
111 views

How do I calculate the moment of inertia with velocity? [closed]

How do I calculate a total moment of inertia when I have point mass with velocity? It looks like this: If I understand correctly, firstly I have to find a center of mass. What do I do next?
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1answer
129 views

How do momentum get transferred?

Simple Question , Consider two objects namely $A$ and $B$ where $B$ is stationary and $A$ is moving towards $B$ with velocity $v$. When the two objects touch each other what does actually happen ...
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How is inertial mass different from gravitational mass? [duplicate]

I recently read that the mass we deal with in Equation $F=M_{i}a$ is called inertial mass and the mass we deal with in $F=M_{g}g$ is gravitational mass. Suppose I take a ball in a free fall and in ...
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2answers
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Double the mass in the universe, double the inertia

If I double (halve) the mass in the visible universe, will my inertia double (halve)? I think it should, at least as soon ''I have received the news of this doubling''. But what does the General ...
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6answers
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If there is no gravity, does that mean there's no mass as well? [duplicate]

I have demonstrated that weight only is measured based on the gravitational pull of where you live. For example, the gravity on the surface of Mars is three times smaller than the gravity on the ...
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0answers
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Charged Universe and charge-dependent inertia/anti-inertia

I posted this same question as a follow up for the main question here. I expected to get a quick answer but since none have come up I raise it as a topic in its own right. So the question is: Suppose ...
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The Inertial theory of Sciama and an electromagnetic analogue

In 1952 D. W. Sciama introduced a paper On the origin of inertia. It presents a method in which inertia could arise from other mass in the universe. It goes along these lines: If you try to ...
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1answer
67 views

Difference between first newton's law and second newton's law ? [duplicate]

the first and second laws of newton are both similar, so why do we need the first law if it is the same as the second? what is the big difference between these?
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1answer
69 views

Is there a gravitational radiation reaction force?

As you may know, the linearized relativity theory (or gravitoelectromagnetism), obeys equations analogous to Maxwell's equations in electrodynamics. These equations in ED result in the troubling ...
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Researching an automobile accident.Wondering if someone can help me as I never studied physics [closed]

I am trying do some independent research on a recent auto collision where the information released doesn't seem plausible based on the pictures that I have seen of the accidents aftermath. A ...
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1answer
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An apparent contradiction to $m = m_0/\sqrt{1-v^2/c^2}$ [duplicate]

Using theoretical framework of the special relativity, we can show that the quantity that we classically regard as energy does have a property of inertia. And particularly, if the total energy of a ...